Virtual reality provides new insight into how different brain areas assemble memories

Posted on February 2, 2018

Dimsdale-Zucker and Professor Charan Ranganath at the UC Davis Center for Neuroscience and Department of Psychology were interested in how the brain assembles all the pieces of these memories. With functional magnetic resonance imaging, or fMRI, to look for brain areas that are activated as memories are recalled, especially in the hippocampus.

The subjects watched a series of videos in which they went into houses built with architectural sketching software in a sequence. In each video, different objects were positioned within the houses. The subjects therefore memorized the objects in two contexts: which video (episodic memory) and which house (spatial memory). In the second phase of the study, the subjects were asked to try to remember the objects while they were scanned by fMRI.

It was noted by Dimsdale-Zucker that being asked about the objects spontaneously reactivated contextual information. It would then follow that different regions of the hippocampus were activated for different kinds of information: One area, CA1, was associated with representing shared information about contexts (e.g., objects that were in the same video); another, distinct area was linked to representing differences in context.

"What's exciting is that it is intuitive that you can remember a unique experience, but the hippocampus is also involved in linking similar experiences," Dimsdale-Zucker said. "You need both to be able to remember." Another breakthrough discovered that the hippocampus was involved in episodic memories linking both time and space contrary to conventional thinking that the hippocampus codes primarily for spatial memories, for example those involved in navigation.